LED Current Regulator Circuit With Self-Adaptive Power Offloading
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Solution Overview
Problem
Current LED driver circuits face challenges in reducing power dissipation, particularly when the power supply voltage varies, leading to overheating issues, and existing solutions such as parallelization or DC/DC regulators are either costly or complex.
Innovation Solution
The implementation of a self-adaptive power offloading concept in LED driver circuits, which uses two or more parallel current paths with a single control loop to regulate the sum of currents through a voltage drop element, dynamically adjusting the power distribution based on sensed current, eliminating the need for additional measurements and reducing silicon area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear current regulators are used to control current to LEDs, then current regulation is achieved, but power dissipation increases causing overheating
Solution Approach 1:
The current regulator circuit is segmented into multiple parallel current paths (first current path with transistor Q1, second current path with transistor Q2 and drop element R2). This segmentation allows the total current to be divided such that power dissipation is reduced within the regulator circuit by routing current through the external drop element in one path while maintaining regulation stability through coordinated control of both paths based on sensed current.
2Loss of energy
If parallel current paths are implemented to reduce power dissipation, then power dissipation decreases, but circuit complexity increases
Solution Approach 1:
Multiple current paths (first current path through Q1 and second current path through Q2 and R2) are merged into a unified control architecture where a single sensed current measurement controls both paths. The control circuit generates coordinated control signals for both transistors Q1 and Q2 based on the same sensed current, reducing the need for separate control circuits and minimizing overall complexity while achieving power dissipation reduction.
Solution Approach 2:
The circuit uses self-service by employing a single sensed current measurement that automatically controls multiple current paths. The sensed current from the combined output automatically regulates both the first current path (through Q1) and the second current path (through Q2 and R2), eliminating the need for additional independent sensing or control circuits for each path.
3Measurement precision
If additional control circuits are added to monitor individual currents in parallel paths, then current control precision improves, but device complexity and cost increase
Solution Approach 1:
The circuit employs self-service by using a single sensed current measurement that automatically controls multiple current paths. The sensed current from the combined output automatically regulates both the first current path (through Q1) and the second current path (through Q2 and R2), eliminating the need for additional independent sensing or control circuits for each path.
Solution Approach 2:
The single sensed current measurement serves multiple functions: it controls the first current path through Q1, controls the second current path through Q2 and R2, and provides overall power dissipation management. This universal control approach achieves precise current control for multiple paths without requiring separate control circuits, thereby reducing complexity while maintaining precision.
Data Source
AI summary
A circuit may be configured to deliver current to one or more light emitting diodes (LEDs). The circuit may comprise a first current path configured to deliver a first current to the one or more LEDs, and a second current path in parallel with the first current path, wherein the second current path is configured to deliver a second current through a voltage drop element and to the one or more LEDs. According to this disclosure, a sum of the first current and the second current is regulated based on a sensed current through the circuit.